Vertically spinning wind mills have been created that may be more cost effective than the three blade style windmills. The vertical wind turbines can capture the wind from various directions and that maximizes the potential of the wind power. When grouped together the vertical wind turbines can reuse the turbulence created by the other turbines.
Imagine a giant room full of oscillating house-fans, the breeze created by some of the fans would be blowing on some of the others at various times. The breeze would ripple outward from each fan in airwaves of wind pulsing with the spin of the fan-blades. The streaming airflow within the area of the fans might be ricocheted back and forth between many of the fans, like a pool ball or pin ball that keeps bouncing off the walls or pinball paddles.
The other advantage besides maximizing capture and reuse of the of the wind and turbine airflow is the size of the vertical wind turbines - they are smaller in size than the three blade windmills, and each take up a smaller square footage of space and more of them can be placed closer together. (image of the spacing and size) The vertical wind turbines may also be safer for wild bird populations.
For video and more information see: Small Turbines can Outperform Conventional Wind Farms, Stanford Prof Says, With No Bird Kill. (forbes.com).
Dabiri Lab of Stanford University (John Dabiri, Ph.D. and team) has an experimental vertical turbine windfarm project in Igiugig Alaska. (dabirilab.com)
Disclaimer: Information provided for educational purposes within guidelines of fair use.